Mineral-flotation apparatus



Jung 3, 1930. R. LORD MINERAL FLOTATION APPARATUS Filed Sept. 1, 1926 2 Sheets-Sheet l R. m N0 WA m. m E w R A TTORNE Y.

R. LORD June 3, 1930.

MINERAL FLOTATION APPARATUS Filed Sept 1, 1926 2 Sheets-Sheet 2 INVENTOR. ROBERT L 0RD A TTORNE Y.

Patented June 3, 1930 UNITED STATES PATENT OFFICE ROBERT LORD, OF CULVER CITY, CALIFORNIA, ABSIGNOR TO SOUTEWE STERN ENGI- NEERING COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALI- FORNIA MINERAL-FLOTATION APPARATUS This invention relates to that typeof mineral flotation machines wherein a rotary aerator is employed for the purpose of agitating the pulp and mixing air therewith to cause separatlon of the values.

19 covery of the sulfide values contained therein, and wherein such aerator may be employed in a simple tank without the necessity for partitions and other complications aside from some means to arrest the prevent surging.

Briefly, the invention resides in a frustoconical hollow aerating rotor whose smaller open end depends in the pulp container and whose upper end carries an apertured head having a driving shaft connected therewith. This aerator is provided with lower and upper. slots, and interiorly with a series of broken spiral rifles whlch assist in elevating the pulp, while its exterior is provided with series of preferably vertical rifles which promote agitation and aeration. During high speed rotation of the aerator air which is drawn through the apertures in the head, is thoroughly mingled with the whirling pulp rising on the interior of the rotor, the aerated mixture being discharged through froth and to the slots. Series of stationary bafles, prefer ably arranged in staggered relation, are vertically disposed around the upper portion of the rotor and extend both above and below the pulp level to arrest the froth being hurled from the rotor, to break said froth into streams and cause entrainment of additional amounts of air. Working in conjunction with the aerator, there is a stationary bafle which is placed below the pulp level on a cell wall and at an angle thereto for the purpose of deflecting the rotating pulp body toward the rotor and prevent surging of the pulp and froth. The invention resides further in the various features and details of construction and in the combinations and arrangements of parts herein set forth.

In the accompanying drawings wherein one embodiment of the invention is disclosed by way of illustration,

Fig. 1 is a plan view of a four cell flotation machine equipped with the invention;

Fig. 2 is a longitudinal vertical section therethrough 1hlig. 3 is a cross section through one of the ce s;

Fig. 4 is a vertical section through the aerator, and

Fig. 5 is a horizontal view taken approximately on the line 55 of Fig. 3.

The apparatus shown comprises a plurality of cells each of which has inclined lower walls 12 converging toward the bottom 13, adjustable side walls 15 working in guides 16 being provided for determining the level of the froth overflowing into the launder 18.

In each of the cells there is mounted one of the aerating rotors 20 of the present invention, this rotor being frusto-conical in form and depending into the pulp with its smaller end open and directed downward. Said rotor 20 is supported by a drive shaft 22, mounted in bearings 24 on timbers 25 and driven by means of gearing 26 from a line shaft 28. The shaft 22 is fixed to a head 30 mounted in the larger and upper end of the rotor 20, whereby the rotor is supported and driven. The head 30 is apertured at 32 for the admission of air to the interior of member 20 to mingle with and be entrained by the swirling and discharging pulp.

The interior of the aerator 20 is provided with a series of broken rifles 34 spirally arranged from bottom to top thereof which rifles serve to assist elevation of the pulp. A port-ion of the pulp is discharged through a series of vertically disposed slots 35 arranged at about the middle of the aerator and having vertically disposed rifles 36 adjacent their edges on the outside of the aerator and at that edge of each slot which is in the direction of rotation of the aerator. The rest of the pulp rises on the interior of the aerator with the assistance of the spiral rifles 34 and is dischargfiad through an up er series of slots 38. On t e outer side of t e aerator below the slots 38 and above slots 35 there is provided a er-iph'eral series of vertically disposed ri es 40 which serve further to agitate and aerate the pulp.

Spaced somewhat from the upper portion of the aerator 20, there is provided an annular series of vertically disposed stationary bafles 44 which extend below the pulp level and above the froth level, said series cooperating preferably with an inner annular series of like bafles 44' staggered with relation thereto. These bafles 44 and 44 are carried by a cap 45 apertured at 46 to receive the shaft 22 and supported on the timber 25 by means of a bracket 48.

Pulp is fed from a pi e 50 into a receiving box 52 at. one end of tiie apparatus whence it passes through inlet 54 into the first compartment 10, being directed according to the direction of travel of aerator 20 by means of a bafle 55 which is mounted on the end wall of the cell at an angle thereto and below the pulp level. This bafle serves not only to direct the inflowing pulp but also to prevent surging, to deflect the swirlin pulp in the cell toward the aerator 20 an to cause the heavy particles to travel down the inclined walls 12 to the center Where they will be picked up by the action of the aerator and be passed-therethrough repeatedly. The pulp passes from one cell to the next through ports 56 in the end walls 14, the bafles 55 in each cell directing the pulp as desired. It will be noted that, as indicated by arrows in Fig. 1, the aerators 20 in adjacent cells rotate in opposite directions, and that in order to properly direct the pulp the bafles 55 are thfirefore inclined oppositely in adjacent ce s.

The pulp level is controlled by an overfiow ate 58 at the end of the apparatus, this gate eing adjustable through the medium of a screw 59 and an adjusting wheel 60. The pulp in leaving the machine passes first under a bafle 62 and then over the gate 58 into the discharge box 64 from which it is conducted by pipe 65. The heavier portions of gangue may be shunted into the dischar e box 64 by a small pipe 66 leading directly rom the last of the cells 10.

If for any reason it is desired to introduce additional amounts of air in order to improve flotation conditions, this may be done as by means of a nozzle 70 supplied from an air line 72, or otherwise.

In operation, the rotation of the aerator causes the pulp to be drawn in through its open lower end and forced upward along its inner walls by centrifugal force and the influence of the spiral rifles 34. This action causes a hollow space to be formed at the upper center portion within the aerator while the pulp itself is thrown out through the lower slots 35 and also through the upper slots 38. At the same time air is forcibly drawn in through the openings 32 in the head 30 of the rotor and is entrained in the pulp as it is hurled through said slots, thus causing positive aeration of the pulp. In addition, the advancing rifles 36 on the outer face of the rotor act to displace the pulp outside said rotor thereby creating a partial vacuum behind each rifle whichassists further in entraining air in the pulp as it passes through the slots 35. Further agitation and aeration of the pulp is produced by the vertical .rifles 40 on the outer wall of the aerator above the slots 35. As a result, the pulp mass is thrown from the upper portion of the rotor in a finely divided form thoroughly mingled with finely diffused air and in a form to produce a large volume of froth. The force of the moving mass is reduced by engagement with the staggered series of bafles 44 and 44' which serve also to break the froth up into streams and to cause entrainment of additional amounts of air. Thus, when the froth and pulp pass out from said bafles 44 and ,44', the maximum amount of froth has been formed and it is in a state for maximum discharge into the launders thereby resulting in maximum recovery of the sulfid values.

With this construction it is not necessary that the cell 10 be divided with partitions to separate a rotor compartment from a settling compartment. On the other hand, the sep aratlon of the froth takes place at the top of the same compartment in which the rotor operates, and at the same time the action of the aerating rotor maintains perfect circulation of the pulp in the cell, assisted only by the action of the deflecting bafle 55 which directs the pulp body toward the aerator and insures passage of the heavier particles to the lower center whereby they are picked up by the pulp stream entering the lower end of the aerator. By rotating the aerators in adjacent cells in opposite directions and by arranging the ba es 55 to assist passage of the pulp in like directions, the pulp body is kept moving in constantl changing directions and the opportunity or maxlmum agitation, aeration and flotation is provided. Vertical arrangement of the bafles 40 on the rotor produces better aeration than an angular arrangement, and an increase in the number thereof increases aeration, although material elongation thereof does not appear to proportionately improve results.

What I claim is:

1. In apparatus for mineral flotation, a hollow frusto-conical aerator adapted to be partially submerged in pulp and having a central pulp chamber having spiral rifles on its inner wall, said aerator having slots therethrough for the discharge of pulp and also having a pulp inlet opening at the lower portion thereof and openings at its upper end for entrance of air into the aerator, and vertically disposed rifles on its outer wall.

2. In apparatus for mineral flotation, a

hollow frusto-conical aerator having a pulp inlet, a compartment receiving the same and adapted to contain pulp, adjustable means to determine the pulp level, said aerator being adapted to work in the 111 and having openings therein for the iso arge of pulp thcrethrough, means on the aerator to assist movement and agitation of the pulp, and vertically disposed bafiles about the upper end of the aerator and extending above the ulp level for intercepting the aerated pulp ody discharge from the aerator.

3. In apparatus for mineral flotation, a cell comprising a sin 1e compartment, a hollow aerator having in ct and discharge openings and mounted to rotate therein and adapted to discharge aerated pulp, baflles arranged about the aerator to intercept the discharged pulp, and a verticall extendin baflle on the cell wall to direct t ward the aerator.

4. In apparatus for mineral flotation,- a plurality of connected cells, an aerator havmg inlet and discharge openin s and rotat ably mounted in each cell and a apted to discharge pulp, the aerators in adjacent cells being rotated in opposite directions, and a deflecting bafile in each cell set at an angle to a wall thereof and adjacent the inlet thereto to direct pulp toward the rotor and in a direction corres onding with the direction of rotation thereoi In witness that I claim the foregoing I have hereunto subscribed my name this 3rd day of August 1926.

ROBERT LORD.

e body 0 the pulp to- 

